On Thu, Oct 16, 2008 at 12:43 AM, Todd Pisek <[EMAIL PROTECTED]> wrote: > Is this typical for these devices?
Hardly, to my understanding random 4k write should take few hundred usec at worst, so 60 writes/sec is either an error in the spec or something unusual in hardware. > Can I extrapolate these numbers linearly? > For example, can I expect ~21 4MB sequential writes per second? I'd rather consult manufacturer - I haven't evaluated Mtron devices myself. Regards, Andrey > > --- Todd > > Andrey Kuzmin wrote: >> >> http://mtron.net/Upload_Data/Spec/ASiC/MOBI/SATA/MSD-SATA3535_rev0.3.pdf, >> Sect. 3.3.1, Table 4, last row. >> >> Regards, >> Andrey >> >> >> >> On Wed, Oct 15, 2008 at 9:10 PM, Eric Sproul <[EMAIL PROTECTED]> wrote: >> >>> >>> Eric Sproul wrote: >>> >>>> >>>> zpool create data raidz c0t4d0 c0t5d0 c0t6d0 c0t7d0 log mirror c2d1 c3d1 >>>> >>> >>> This box has 8 cores (2x quad-core Xeon) and 32GB RAM. >>> >>> We've been running Postgres 8.3 stress tests (pgbench), but we see some >>> odd >>> results. Looking at 'iostat -xn' we see what looks like a bottleneck on >>> the ZIL >>> devices: >>> >>> extended device statistics >>> r/s w/s kr/s kw/s wait actv wsvc_t asvc_t %w %b device >>> 0.0 102.0 0.0 6527.7 0.0 1.0 0.0 9.4 0 96 c2d1 >>> 0.0 101.0 0.0 6399.7 0.0 1.0 0.0 9.5 0 95 c3d1 >>> 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0 0 c1t1d0 >>> 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0 0 c0t2d0 >>> 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0 0 c0t3d0 >>> 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0 0 c0t4d0 >>> 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0 0 c0t5d0 >>> 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0 0 c0t6d0 >>> 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0 0 c0t7d0 >>> ` extended device statistics >>> r/s w/s kr/s kw/s wait actv wsvc_t asvc_t %w %b device >>> 0.0 102.0 0.0 5072.0 0.0 1.0 0.0 9.4 0 96 c2d1 >>> 0.0 103.0 0.0 5200.0 0.0 0.9 0.0 9.0 0 92 c3d1 >>> 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0 0 c1t1d0 >>> 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0 0 c0t2d0 >>> 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0 0 c0t3d0 >>> 0.0 55.0 0.0 1458.5 0.0 0.9 0.0 17.1 0 24 c0t4d0 >>> 0.0 53.0 0.0 1458.5 0.0 0.8 0.0 15.8 0 24 c0t5d0 >>> 0.0 57.0 0.0 1456.5 0.0 1.5 0.0 25.7 0 29 c0t6d0 >>> 0.0 63.0 0.0 1438.0 0.0 1.1 0.0 17.3 0 22 c0t7d0 >>> extended device statistics >>> r/s w/s kr/s kw/s wait actv wsvc_t asvc_t %w %b device >>> 0.0 101.0 0.0 5608.3 0.0 1.0 0.0 9.4 0 95 c2d1 >>> 0.0 101.0 0.0 5608.3 0.0 1.0 0.0 9.4 0 95 c3d1 >>> 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0 0 c1t1d0 >>> 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0 0 c0t2d0 >>> 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0 0 c0t3d0 >>> 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0 0 c0t4d0 >>> 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0 0 c0t5d0 >>> 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0 0 c0t6d0 >>> 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0 0 c0t7d0 >>> extended device statistics >>> r/s w/s kr/s kw/s wait actv wsvc_t asvc_t %w %b device >>> 0.0 102.0 0.0 6528.0 0.0 1.0 0.0 9.4 0 95 c2d1 >>> 0.0 102.0 0.0 6528.0 0.0 0.9 0.0 9.0 0 92 c3d1 >>> 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0 0 c1t1d0 >>> 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0 0 c0t2d0 >>> 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0 0 c0t3d0 >>> 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0 0 c0t4d0 >>> 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0 0 c0t5d0 >>> 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0 0 c0t6d0 >>> 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0 0 c0t7d0 >>> extended device statistics >>> r/s w/s kr/s kw/s wait actv wsvc_t asvc_t %w %b device >>> 0.0 100.0 0.0 6399.8 0.0 1.0 0.0 9.6 0 96 c2d1 >>> 0.0 100.0 0.0 6399.8 0.0 1.0 0.0 9.6 0 96 c3d1 >>> 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0 0 c1t1d0 >>> 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0 0 c0t2d0 >>> 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0 0 c0t3d0 >>> 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0 0 c0t4d0 >>> 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0 0 c0t5d0 >>> 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0 0 c0t6d0 >>> 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0 0 c0t7d0 >>> >>> We never see more than about 100 write ops/second on the SSDs, which >>> seems >>> really low to me, and it also seems odd that they are 95-96% utilized at >>> that >>> rate. The pgbench test is primarily doing updates with some percentage >>> of >>> inserts thrown in, and the entire database fits into RAM, which is why we >>> see >>> very little activity on the raidz disks, but lots on the ZIL, since >>> there's a >>> ton of fsync() from Postgres. >>> >>> I was expecting much higher IOPS on the SSDs. Can anyone help me >>> understand >>> what's going on here? >>> >>> Thanks, >>> Eric >>> _______________________________________________ >>> storage-discuss mailing list >>> [email protected] >>> http://mail.opensolaris.org/mailman/listinfo/storage-discuss >>> >>> >> >> _______________________________________________ >> storage-discuss mailing list >> [email protected] >> http://mail.opensolaris.org/mailman/listinfo/storage-discuss >> > > _______________________________________________ storage-discuss mailing list [email protected] http://mail.opensolaris.org/mailman/listinfo/storage-discuss
